Dresden 2011 – wissenschaftliches Programm

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AKE: Arbeitskreis Energie

AKE 8: Offshore Wind

AKE 8.2: Vortrag

Mittwoch, 16. März 2011, 11:45–12:00, BEY 118

Intermittent Structures in Atmospheric Wind Fields — •Örsan Yüksek, Tanja Mücke, and Joachim Peinke — ForWind Center for Wind Energy Research, University of Oldenburg, Germany

For design processes and load calculations of wind energy convertors (WEC) realistic synthetic wind fields are needed. The widely used norm is the standard IEC 61400. The IEC standard considers different simulation methods based on Gaussian statistics. However, the analysis of the measured wind fields by means of velocity increment statistics yields that these do not obey Gaussian statistics but are quite intermittent. The intermittent nature of atmospheric wind affects the whole chain of the wind energy conversion process and is assumed to be a major effect for additional loads and fatigue. A recently proposed method based on continuous time random walks (CTRWs) adequately reproduces the intermittency of turbulent atmospheric velocity increments on small time scales and provides wind fields with the desired high order two point statistics. In this work, we analyze highly time-resolved data sets measured in an extensive grid over the whole rotor plane of a WEC. The atmospheric wind fields are characterized statistically and the dependency of the higher order two point statistics on turbulence intensity, mean wind speed and height is shown. With this knowledge we are able to generate synthetic CTRW wind fields with the correct small scale structure.